Architecture
LatticeECP2/M Family Data Sheet
Lattice Semiconductor
2. Write Through – A copy of the input data appears at the output of the same port during a write cycle.This mode
is supported for all data widths.
Memory Core Reset
The memory array in the EBR utilizes latches at the A and B output ports. These latches can be reset asynchro-
nously or synchronously. RSTA and RSTB are local signals, which reset the output latches associated with Port A
and Port B, respectively. The Global Reset (GSRN) signal resets both ports. The output data latches and associ-
ated resets for both ports are as shown in Figure 2-20.
Figure 2-20. Memory Core Reset
SET
D
Q
Memory Core
Port A[17:0]
Port B[17:0]
LCLR
Output Data
Latches
SET
D
Q
LCLR
RSTA
RSTB
GSRN
Programmable Disable
For further information about the sysMEM EBR block, please see the the list of additional technical documentation
at the end of this data sheet.
EBR Asynchronous Reset
EBR asynchronous reset or GSR (if used) can only be applied if all clock enables are low for a clock cycle before the
reset is applied and released a clock cycle after the reset is released, as shown in Figure 2-21. The GSR input to the
EBR is always asynchronous.
Figure 2-21. EBR Asynchronous Reset (Including GSR) Timing Diagram
Reset
Clock
Clock
Enable
If all clock enables remain enabled, the EBR asynchronous reset or GSR may only be applied and released after
the EBR read and write clock inputs are in a steady state condition for a minimum of 1/f
(EBR clock). The reset
MAX
release must adhere to the EBR synchronous reset setup time before the next active read or write clock edge.
2-20
LATTICE [ LATTICE SEMICONDUCTOR ]
